diff --git a/Lib/imaplib.py b/Lib/imaplib.py index 724f9d13a04..3f6656a7625 100644 --- a/Lib/imaplib.py +++ b/Lib/imaplib.py @@ -43,6 +43,15 @@ IMAP4_PORT = 143 IMAP4_SSL_PORT = 993 AllowedVersions = ('IMAP4REV1', 'IMAP4') # Most recent first +# Maximal line length when calling readline(). This is to prevent +# reading arbitrary length lines. RFC 3501 and 2060 (IMAP 4rev1) +# don't specify a line length. RFC 2683 however suggests limiting client +# command lines to 1000 octets and server command lines to 8000 octets. +# We have selected 10000 for some extra margin and since that is supposedly +# also what UW and Panda IMAP does. +_MAXLINE = 10000 + + # Commands Commands = { @@ -256,7 +265,10 @@ class IMAP4: def readline(self): """Read line from remote.""" - return self.file.readline() + line = self.file.readline(_MAXLINE + 1) + if len(line) > _MAXLINE: + raise self.error("got more than %d bytes" % _MAXLINE) + return line def send(self, data): diff --git a/Lib/test/test_imaplib.py b/Lib/test/test_imaplib.py index 7db3f7dddc1..daa8afeec55 100644 --- a/Lib/test/test_imaplib.py +++ b/Lib/test/test_imaplib.py @@ -325,6 +325,17 @@ class BaseThreadedNetworkedTests(unittest.TestCase): self.assertEqual(ret, "OK") + def test_linetoolong(self): + class TooLongHandler(SimpleIMAPHandler): + def handle(self): + # Send a very long response line + self.wfile.write(b'* OK ' + imaplib._MAXLINE*b'x' + b'\r\n') + + with self.reaped_server(TooLongHandler) as server: + self.assertRaises(imaplib.IMAP4.error, + self.imap_class, *server.server_address) + + class ThreadedNetworkedTests(BaseThreadedNetworkedTests): server_class = socketserver.TCPServer diff --git a/Misc/NEWS b/Misc/NEWS index b450f357ec0..be6c82afb00 100644 --- a/Misc/NEWS +++ b/Misc/NEWS @@ -5,9 +5,9 @@ Python News What's New in Python 3.3.3 release candidate 1? =============================================== -*Not yet released, see sections below for changes released in 3.3.2* +.. *Not yet released, see sections below for changes released in 3.3.2* -.. *Release date: TBD* +*Release date: 27-Oct-2013* Core and Builtins ----------------- @@ -81,6 +81,9 @@ Core and Builtins Library ------- +- Issue #16039: CVE-2013-1752: Change use of readline in imaplib module to limit + line length. Patch by Emil Lind. + - Issue #19393: Fix symtable.symtable function to not be confused when there are functions or classes named "top". @@ -425,7 +428,8 @@ C API ----- - Issue #18351: Fix various issues with a helper function in importlib used - by PyImport_ExecCodeModuleWithPathnames() (and thus by extension PyImport_ExecCodeModule() and PyImport_ExecCodeModuleEx()). + by PyImport_ExecCodeModuleWithPathnames() (and thus by extension + PyImport_ExecCodeModule() and PyImport_ExecCodeModuleEx()). IDLE ----